In-cell touch display device

ABSTRACT

An in-cell touch display device. A panel has a plurality of data lines, a plurality of gate lines and a plurality of touch electrodes disposed thereon. A touch driving signal is applied to the plurality of touch electrodes when a driving mode is a touch mode. A data driver drives the plurality of data lines. A gate driver drives the plurality of gate lines. The gate driver sequentially outputs a scanning signal for driving the plurality of gate lines to the plurality of gate lines when the driving mode is a display mode, and outputs a load-free driving signal corresponding to the touch driving signal to at least one gate line when the driving mode is the touch mode. A level shifter generates the load-free driving signal. A multiplexer inputs a scanning voltage or the load-free driving signal to the gate driver depending on the driving mode.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit under 35 U.S.C.§119(a) of Korean Patent Application No. 10-2014-0090038 filed on Jul.16, 2014, which is hereby incorporated by reference for all purposes asif fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an in-cell touch display device.

2. Description of Related Art

In response to the development of the information society, there is anincreased demand for various types of display devices able to displayimages. Currently, various display devices, such as liquid crystaldisplays (LCDs), plasma display panels (PDPs) and organic light-emittingdiode (OLED) displays, are used.

Many display devices provide a touch-based input system enabling usersto intuitively and conveniently input information or instructionsdirectly to a device screen, rather than using conventional inputsystems, such as buttons, a keyboard and a mouse.

In order to provide such a touch-based input system, sensitivity to thetouch of a user and the ability to accurately detect coordinates of atouched point are required.

For this, in the related art, touch sensing is provided using a touchsensing method selected from among a variety of touch sensingtechnologies, such as resistive touch sensing technology, capacitivetouch sensing technology, electromagnetic induction technology, infrared(IR) touch sensing technology and ultrasonic touch sensing technology.

Among the variety of touch sensing technologies, capacitive touchsensing technology is popular. This technology uses a plurality of touchelectrodes (e.g., row electrodes and column electrodes) formed on atouchscreen panel to detect a touch and coordinates of a touched pointbased on a change in the capacitance between touch electrodes or betweena pointer, such as a finger, and a touch electrode.

According to the capacitive touch sensing technology, in addition tocapacitance necessary for touch sensing, undesirable parasiticcapacitance is generated by other voltage lines or electrodessurrounding touch electrodes.

The undesirable parasitic capacitance causes certain problems, forexample, increasing the load of a touch operation, lowering the accuracyof touch sensing, and in severe cases, making touch sensing impossible.

The problems caused by such undesirable parasitic capacitance frequentlyoccur in in-cell display devices inside which a touchscreen panel (TSP)is integrally provided using “in-cell” technology.

BRIEF SUMMARY OF THE INVENTION

Various aspects of the present invention provide an in-cell touchdisplay device able to prevent parasitic capacitance that wouldotherwise increase the load of a touch operation, lower the accuracy oftouch sensing, or make touch sensing impossible.

Also the present invention is directed to an in-cell touch displaydevice providing an efficient gate line driving system that can preventparasitic capacitance.

Also the present invention is directed to an in-cell touch displaydevice able to prevent parasitic capacitance without a change in thedesign of existing parts, such as a gate driver and a power managementintegrated circuit.

In an aspect of the present invention, there is an in-cell touch displaydevice that includes: a panel comprising a plurality of data lines, aplurality of gate lines and a plurality of touch electrodes disposedthereon, wherein a touch driving signal is applied to the plurality oftouch electrodes when a driving mode is touch mode; a data driverdriving the plurality of data lines; a gate driver driving the pluralityof gate lines, wherein the gate driver sequentially outputs a scanningsignal for driving the plurality of gate lines to the plurality of gatelines when the driving mode is display mode, and outputs a load-freedriving signal corresponding to the touch driving signal to at least onegate line of the plurality of gate lines when the driving mode is thetouch mode; a level shifter generating the load-free driving signal; anda multiplexer inputting a scanning voltage or the load-free drivingsignal to the gate driver depending on the driving mode.

According to one or more embodiments of the present invention as setforth above, the in-cell touch display device can prevent parasiticcapacitance that would otherwise increase the load of the touchoperation, lower the accuracy of the touch sensing, or make the touchsensing impossible.

In addition, according to one or more embodiments of the presentinvention, the in-cell touch display device provides an efficient gateline driving system that can prevent parasitic capacitance.

Furthermore, according to one or more embodiments of the presentinvention, the in-cell touch display device can prevent parasiticcapacitance without a change in the design of existing parts, such asthe gate driver and the power management integrated circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more clearly understood from the following detaileddescription when taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a schematic system configuration view illustrating an in-celltouch display device according to an exemplary embodiment of the presentinvention;

FIG. 2 illustrates the in-cell touchscreen panel illustrated in FIG. 1;

FIG. 3 conceptually illustrates a signal applied to a common electrodedepending on the driving mode of the in-cell touch display deviceaccording to an exemplary embodiment of the present invention;

FIG. 4 illustrates capacitance components occurring in the in-cell touchdisplay device according to an exemplary embodiment of the presentinvention;

FIG. 5 conceptually illustrates an application of a signal to a dataline and a gate line in order to prevent parasitic capacitance in thein-cell touch display device according to an exemplary embodiment of thepresent invention when the driving mode is touch mode;

FIG. 6 conceptually illustrates a signal waveform applied to a commonelectrode, a data line and a gate line depending on the driving mode ofthe in-cell touch display device according to an exemplary embodiment ofthe present invention;

FIG. 7 illustrates a signal applying structure in a unit touch area ofthe in-cell touch display device according to an exemplary embodiment ofthe present invention; and

FIG. 8 conceptually illustrates a circuit in which the gate driveroutputs a scanning signal or a load-free driving signal depending on thedriving mode of the in-cell touch display device according to anexemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the present invention,embodiments of which are illustrated in the accompanying drawings.Throughout this document, reference should be made to the drawings, inwhich the same reference numerals and signs may be used throughout thedifferent drawings to designate the same or similar components. In thefollowing description of the present invention, detailed descriptions ofknown functions and components incorporated herein will be omitted inthe case that the subject matter of the present invention may berendered unclear thereby.

It will also be understood that, although terms such as “first,”“second,” “A,” “B,” “(a)” and “(b)” may be used herein to describevarious elements, such terms are only used to distinguish one elementfrom another element. The substance, sequence, order or number of theseelements is not limited by these terms. It will be understood that whenan element is referred to as being “connected to” or “coupled to”another element, not only can it be “directly connected” or “coupled to”the other element, but also can it be “indirectly connected or coupledto” the other element via an “intervening” element. In the same context,it will be understood that when an element is referred to as beingformed “on” or “under” another element, not only can it be directlyformed on or under another element, but also can it be indirectly formedon or under another element via an intervening element.

FIG. 1 is a schematic system configuration view illustrating an in-celltouch display device 100 according to an exemplary embodiment of thepresent invention.

Referring to FIG. 1, the in-cell touch display device 100 includes apanel 110 on which a plurality of data lines DL, a plurality of gatelines GL and a plurality of touch electrodes are disposed, a data driver120 for driving the plurality of data lines DL, a gate driver 130 fordriving the plurality of gate lines GL, and a timing controller 140 forcontrolling the data driver 120 and the gate driver 130.

In the in-cell touch display device 100 according to an exemplaryembodiment illustrated in FIG. 1, the data driver 120 may include atleast one data driver integrated circuit (DDIC).

The DDIC may be connected to the bonding pads of the panel 110 by tapeautomated bonding (TAB) or chip-on-glass (COG) bonding, or in somecases, may be integrated with the panel 110.

In the in-cell touch display device 100 according to an exemplaryembodiment illustrated in FIG. 1, the gate driver may be positioned onone side of the panel 110, as illustrated in FIG. 1. Alternatively, thegate driver may also be divided into two sections that are positioned onboth sides of the panel 110 depending on the driving method.

The gate driver unit 130 may further include at least one gate driverintegrated circuit (GDIC).

The GDIC may be connected to the bonding pads of the panel 110 by tapeautomated bonding (TAB) or chip-on-glass (COG) bonding, may beimplemented as a gate-in-panel (GIP) type GDIC that is directly providedon the panel 110, or in some cases, may be integrated with the panel110.

On the panel 110 of the in-cell touch display device 100 according to anexemplary embodiment illustrated in FIG. 1, a plurality of pixels may beformed at a plurality of points in which the plurality of data lines DLand the plurality of gate lines GL intersect each other. Here, each ofthe pixels may consist of three or four sub-pixels or may be a singlesub-pixel.

The panel 110 of the in-cell touch display device 100 according to anexemplary embodiment illustrated in FIG. 1 can function as both adisplay panel and a touchscreen panel. That is, the panel 110 canfunction as a “display panel” in a display mode, and can function as a“touchscreen panel” in a touch mode.

In this sense, the panel 110 of the in-cell touch display device 100according to an exemplary embodiment is referred to as “a display panelwith which a touchscreen panel is integrated,” “a display panel insidewhich a touchscreen panel is provided,” or “an in-cell touchscreendisplay panel.”

With the plurality of touch electrodes disposed on the panel 110 of thein-cell touch display device 100 according to an exemplary embodiment,the panel 110 can function as a touchscreen panel.

The “plurality of touch electrodes” may be “touch mode electrodes” towhich a touch signal is applied only when the driving mode of thedisplay device is a touch mode, or may be “common mode electrodes” towhich a display driving signal (e.g. a common voltage) is applied in adisplay mode and a touch driving signal (TDS) is applied in a touchmode.

When the plurality of touch electrodes are the common mode electrodes,for example, a plurality of common electrodes (CEs) formed as blocks onthe panel 110 can be used as a plurality of touch electrodes. That is,the plurality of touch electrodes can be a plurality of commonelectrodes to which the common voltage Vcom is applied. Here, the commonvoltage Vcom refers to a voltage that must be supplied to all pixels forthe purpose of displaying an image.

In this case, the plurality of touch electrodes corresponding to theplurality of common electrodes formed as blocks on the panel 110 havethe common voltage applied thereto as a display driving signal when thedriving mode of the display device is display mode, and have at leastone touch driving signal applied thereto when the driving mode of thedisplay device is a touch mode.

In this regard, in an example, when the in-cell touch display device 100is a liquid crystal display (LCD), the plurality of common electrodesformed as blocks on the panel 110 may be a plurality of commonelectrodes to which the common voltage Vcom is applied in order to forman electric field corresponding to each of pixel electrodes to which apixel voltage is applied.

In another example, when the in-cell touch display device 100 is anorganic light-emitting diode (OLED) display, the plurality of commonelectrodes formed as blocks on the panel 110 are the cathode electrodes(common electrodes) of a plurality of organic light-emitting diodes(OLEDs) corresponding to the anode electrodes (pixel electrodes) of theplurality of OLEDs. In the following, for the sake of explanation, itwill be illustrated that the touch electrodes are formed as the commonmode electrodes to which a corresponding signal is applied in eitherdisplay mode or touch mode and that the common electrodes to which thecommon voltage Vcom is applied for the purpose of displaying an imagefunction as touch electrodes. Therefore, the touch electrodes will bereferred to hereinafter as the common electrodes.

The plurality of common electrodes formed on the panel 110 of thein-cell touch display device 100 according to an exemplary embodimentare one of the parts that enable the panel 110 to function as both adisplay panel and a touchscreen panel.

The plurality of common electrodes function as “common voltageelectrodes” to which a common voltage Vcom is applied in a display mode,enabling the panel 110 to function as a display panel. In a touch mode,the plurality of common electrodes function as the “touch electrodes” towhich a touch driving signal is applied, enabling the panel 110 tofunction as a touch screen.

In other words, when the driving mode of the display device is displaymode, the common voltage Vcom is applied to the plurality of commonelectrodes. When the driving mode of the display device is a touch mode,a touch driving signal is applied to at least one of the plurality ofcommon electrodes.

In the common electrodes, the term “common” indicates not only that thecommon voltage is applied to the common electrodes, but also that thecommon electrodes can function as both common voltage electrodesrequired for a display mode and touch electrodes required for a touchmode.

The in-cell touch display device 100 according to an exemplaryembodiment may be an LCD or an OLED display.

A detailed description will be given below of the in-cell touchscreenpanel 110 according to an exemplary embodiment.

FIG. 2 illustrates the in-cell touchscreen panel 110 according to anexemplary embodiment.

Referring to FIG. 2, the in-cell touchscreen panel 110 according to anexemplary embodiment has the plurality of data lines DL and theplurality of gate lines GL formed thereon, with which the in-celltouchscreen panel 110 can function as a display panel.

Referring to FIG. 2, the in-cell touchscreen panel 110 according to anexemplary embodiment has the plurality of common electrodes formedthereon, with which the in-cell touchscreen panel 110 can function asboth a display panel and a touchscreen panel. The plurality of commonelectrodes function as common voltage electrodes to which a commonvoltage is applied in a display mode and function as touch electrodes towhich a touch driving signal is applied in a touch mode.

The in-cell touchscreen panel 110 illustrated in FIG. 2 has twelvecommon electrodes CE11, CE12, CE13, CE14, CE21, CE22, CE23, CE24, CE31,C332, CE33 and CE34 formed thereon.

Referring to FIG. 2, the size of each of the plurality of commonelectrodes CE11, CE12, CE13, CE14, CE21, CE22, CE23, CE24, CE31, C332,CE33 and CE34 corresponds to the size of a group of pixels.

In addition, referring to FIG. 2, each of the plurality of commonelectrodes CE11, CE12, CE13, CE14, CE21, CE22, CE23, CE24, CE31, C332,CE33 and CE34 is in the shape of, for example, a block. The blocks ofthe common electrodes are separated from each other.

In addition, depending on the driving mode, there is required a signalapplying structure for applying a common voltage Vcom or a touch drivingsignal to each of the plurality of common electrodes CE11, CE12, CE13,CE14, CE21, CE22, CE23, CE24, CE31, C332, CE33 and CE34.

For this, as illustrated in FIG. 2, the in-cell touchscreen panel 110according to an exemplary embodiment has signal lines formed thereon,the signal lines being respectively connected to the plurality of commonelectrodes corresponding to the touch electrodes.

That is, the number of the signal lines is the same as the number of thecommon electrodes corresponding to the touch electrodes.

Referring to FIG. 2, the signal lines are formed in the same directionas the data lines DL. Alternatively, the signal lines may be formed inthe same direction as the gate lines GL.

Twelve signal lines SL11, SL12, SL13, SL14, SL21, SL22, SL23, SL24,SL31, SL32, SL33 and SL34 are formed on the in-cell touchscreen panel110 according to an exemplary embodiment illustrated in FIG. 2.

Each of the signal lines transfers the common voltage to the connectedcommon electrode in a display mode, and transfers a touch driving signalto the connected common electrode in a touch mode.

FIG. 3 conceptually illustrates a signal (Vcom or TDS) applied to acommon electrode CE depending on the driving mode of the in-cell touchdisplay device 100 according to an exemplary embodiment.

Referring to FIG. 3, the in-cell touch display device 100 according toan exemplary embodiment has two driving modes, i.e., a display mode anda touch mode.

Referring to FIG. 3, the driving mode of the in-cell touch displaydevice 100 according to an exemplary embodiment can be divided into thedisplay mode and the touch mode in one frame period through timedivision.

Referring to FIG. 3, in a display mode period in one frame period, acommon voltage Vcom is applied to all of the plurality of commonelectrodes CE through all of the signal lines.

Referring to FIG. 3, in a touch mode period following the display modeperiod in one frame period, a touch driving signal TDS is sequentiallyapplied to one of the plurality of common electrodes CE corresponding tothe touch electrodes through a corresponding signal line.

When the touch driving signal TDS is applied to one common electrode,the touch driving signal TDS can be applied simultaneously to at leastone adjacent common electrode.

As described above, in the touch mode period, a touch sensing operationis performed in response to the touch driving signal TDS beingsequentially applied to the common electrodes CE corresponding to thetouch electrodes.

In this regards, the in-cell touch display device 100 according to anexemplary embodiment can employ capacitive touch sensing technology fortouch technology. The capacitive touch sensing technology allows for thedetection of a touch, coordinates of a touched point and the like basedon a change in capacitance through the plurality of common electrodes CEformed as touch electrodes on the panel 110 functioning as a touchscreenpanel.

The capacitive touch sensing technology is divided, for example, intomutual capacitive touch sensing and self-capacitive touch sensing.

First, according to the mutual capacitive touch sensing that is one typeof the capacitive touch sensing technology, among row electrodes (eachof which may be referred to as a group of common electrodes arranged ona single row) and column electrodes (each of which may be referred to asa group of common electrodes arranged on a single column), electrodesarranged in a row (or in a column) function as transmitting (Tx)electrodes (also referred to as driving electrodes) to which a drivingvoltage (touch driving signal) is applied, and electrodes arranged in acolumn (or in a row) function as receiving (Rx) electrodes (alsoreferred to as sensing electrodes) that sense the driving voltage andgenerate capacitance (mutual capacitance) together with the Txelectrodes. A touch and coordinates of a touched point are detectedbased on a change in the capacitance (mutual capacitance) between the Txand Rx electrodes depending on whether or not a pointer, such as afinger or a pen, is present.

In addition, according to the self-capacitive touch sensing that isanother type of the capacitive touch sensing technology, the commonelectrodes CE functioning as touch electrodes generate capacitance(self-capacitance) with a pointer, such as a finger or a pen. Here, acapacitance value between a touch electrode and the pointer depending onwhether or not the pointer is present is measured, and a touch andcoordinates of a touched point are detected based on the measuredcapacitance value. Unlike from the mutual capacitive touch sensing,according to the self-capacitive touch sensing, a driving voltage (touchdriving signal) is simultaneously applied and sensed through each of thecommon electrodes CE functioning as touch electrodes.

The in-cell touch display device 100 according to an exemplaryembodiment can employ one of the above-mentioned two types of capacitivetouch sensing (the mutual capacitive touch sensing and theself-capacitive touch sensing). However, it will be described herein onthe assumption that the self-capacitive touch sensing is employed inthis embodiment for the sake of explanation.

FIG. 4 illustrates capacitance components occurring in the in-cell touchdisplay device 100 according to an exemplary embodiment.

As described above, a common electrode CE is a common mode electrodethat functions as a touch electrode to which a touch driving signal isapplied in a touch mode and functions as a common voltage electrode towhich a common voltage Vcom to be supplied to all pixels is applied in adisplay mode. Referring to FIG. 4, in the touch mode period, the commonelectrode CE generates capacitance Cself together with a pointer, suchas a finger or a pen, in order to detect a touch and coordinates of atouched point. The common electrode CE may also generate undesirableparasitic capacitance components Cpara1 and Cpara2 together with a dataline DL and a gate line GL.

The parasitic capacitances Cpara1 and Cpara2 undesirably occurring inthe touch mode act as a significant load in a touch operation to lowerthe accuracy of touch sensing or disable the touch sensing.

The parasitic capacitance Cpara may cause worse problems in the touchsensing since the size thereof increases with the increasing size of thedisplay device 100 or the display panel 110.

Therefore, the in-cell touch display device 100 according to anexemplary embodiment has a configuration devised to prevent theparasitic capacitance Cpara that would otherwise act as a significantload in the touch operation.

FIG. 5 conceptually illustrates an application of a signal to a dataline DL and a gate line GL in order to prevent parasitic capacitanceCpara in the in-cell touch display device 100 according to an exemplaryembodiment when the driving mode is touch mode.

Referring to FIG. 5, when a touch driving signal TDS is applied to acommon electrode CE corresponding to a touch electrode in a touch modeperiod, it is possible to prevent the parasitic capacitance Cpara fromoccurring between the common electrode CE and the gate line GL byremoving the difference in the potential between the common electrode CEand the gate line GL.

Referring to FIG. 5, the gate driver 130 can output a load-free drivingsignal LFDS_gate to at least one gate line in order to remove thedifference in the potential between the common electrode CE and the gateline GL. The load-free driving signal LFDS_gate corresponds to the touchdriving signal TDS applied to the common electrode CE corresponding tothe touch electrode.

The gate driver 130 can output the load-free driving signal LFDS_gate toall of the gate lines, or can output the load-free driving signalLFDS_gate to at least one gate line formed at a position correspondingto at least one common electrode CE to which the touch driving signalTDS is applied, i.e., a position in which the at least one gate line canform parasitic capacitance with the at least one common electrode CE towhich the touch driving signal TDS is applied.

The load-free driving signal LFDS_gate output to the gate line GL canbe, for example, a signal that is identical to the touch driving signalTDS.

For example, as illustrated in FIG. 5, when the touch driving signal TDSis a modulated signal in the form of a square wave alternating between ahigh level and a low level with a predetermined voltage width, thevoltage width and phase of the load-free driving signal LFDS_gate outputto the gate line GL may have may be the same as those of the touchdriving signal TDS.

Likewise, referring to FIG. 5, when the touch driving signal TDS isapplied to the common electrode CE corresponding to a touch electrode inthe touch mode period, it is possible to prevent parasitic capacitancefrom occurring between the common electrode CE and the data line DL byremoving the difference in the potential between the common electrode CEand the data line DL.

Referring to FIG. 5, in the touch mode, the data driver data driver 120can output a load-free driving signal LFDS_data corresponding to thetouch driving signal TDS to a plurality of data lines DL in order toremove the difference in the potential between the common electrode CEand the data line DL.

The data driver 120 can output the load-free driving signal LFDS_data toall of the data lines, or can output the load-free driving signalLFDS_data to at least one data line formed at a position correspondingto at least one common electrode CE to which the touch driving signalTDS is applied, i.e., a position in which the at least one data line canform parasitic capacitance with the at least one common electrode CE towhich the touch driving signal TDS is applied.

The load-free driving signal LFDS_data output the data line DL can be,for example, a signal that is identical to the touch driving signal TDSapplied to the common electrode CE.

For example, as illustrated in FIG. 5, when the touch driving signal TDSis a modulated signal in the form of a square wave alternating between ahigh level and a low level with a predetermined voltage width, thevoltage width and phase of the load-free driving signal LFDS_data outputto the data line DL may be the same as those of the touch driving signalTDS.

In addition, the load-free driving signal LFDS_gate output to the gateline GL may be identical to the load-free driving signal LFDS_dataoutput to the data line DL.

In the in-cell touch display device 100 according to an exemplaryembodiment, a load-free driving signal is divided into a load-freedriving signal LFDS_data output to a data line and a load-free drivingsignal LFDS_gate output to a gate line. This signal is an additionalsignal that is intended to prevent parasitic capacitance, does not havean effect on either the touch sensing operation or the displayoperation, and corresponds to a touch driving signal TDS applied to thecommon electrodes CE functioning as touch electrodes.

FIG. 6 conceptually illustrates a signal waveform applied to a commonelectrode CE, a data line DL and a gate line GL depending on the drivingmode (i.e., a display mode and a touch mode) of the in-cell touchdisplay device 100 according to an exemplary embodiment.

Referring to FIG. 6, when the driving mode is a display mode, the datadriver 120 outputs a data voltage Vdata through the data line DL. Thegate driver 130 outputs a scanning signal to the corresponding gate lineGL. The scanning signal has a high-level voltage VGH present for oneshort period and a low-level voltage VGL present for the remaining longperiod during one frame period.

In addition, when the driving mode is the display mode, the commonvoltage Vcom supplied from a common voltage supply 720 (see FIG. 7) tobe described later is applied to the plurality of common electrodesCE11, CE12, CE13, CE14, CE21, CE22, CE23, CE24, CE31, CE32, CE33 andCE34 (see FIG. 2) through the plurality of signal lines SL11, SL12,SL13, SL14, SL21, SL22, SL23, SL24, SL31, SL32, SL33 and SL34 (see FIG.2).

The common voltage Vcom can be transferred from the common voltagesupply 720 (see FIG. 7) to the data driver 120, from which the commonvoltage Vcom can be output to the plurality of signal lines SL11, SL12,SL13, SL14, SL21, SL22, SL23, SL24, SL31, SL32, SL33 and SL34. In somecases, the common voltage Vcom can be output from the common voltagesupply 720 (see FIG. 7) to the plurality of signal lines SL11, SL12,SL13, SL14, SL21, SL22, SL23, SL24, SL31, SL32, SL33 and SL34 withoutpassing through the data driver 120.

When the driving mode is a touch mode, the touch driving signal TDS isapplied to at least one of the plurality of common electrodes CE11,CE12, CE13, CE14, CE21, CE22, CE23, CE24, CE31, CE32, CE33 and CE34corresponding to the touch electrodes through at least one of theplurality of signal lines SL11, SL12, SL13, SL14, SL21, SL22, SL23,SL24, SL31, SL32, SL33 and SL34.

In an example, the touch driving signal TDS can be output to at leastone of the plurality of signal lines SL11, SL12, SL13, SL14, SL21, SL22,SL23, SL24, SL31, SL32, SL33 and SL34 through the data driver 120 afterbeing generated by a touch sensing unit 710 (see FIG. 7) to be describedlater.

In some cases, the touch driving signal TDS can be directly output to atleast one of the plurality of signal lines SL11, SL12, SL13, SL14, SL21,SL22, SL23, SL24, SL31, SL32, SL33 and SL34 after being generated by thetouch sensing unit 710 (see FIG. 7) to be described later.

When the driving mode is the touch mode, when the touch driving signalTDS is applied to at least one of the plurality of common electrodesCE11, CE12, CE13, CE14, CE21, CE22, CE23, CE24, CE31, CE32, CE33 andCE34 corresponding to touch electrodes through at least one of theplurality of signal lines SL11, SL12, SL13, SL14, SL21, SL22, SL23,SL24, SL31, SL32, SL33 and SL34, the data driver 120 can output theload-free driving signal LFDS_data corresponding to the touch drivingsignal TDS to the data line DL and the gate driver 130 can output theload-free driving signal LFDS_gate corresponding to the touch drivingsignal TDS to the gate line GL.

FIG. 7 illustrates a signal applying structure in a unit touch area ofthe in-cell touch display device 100 according to an exemplaryembodiment.

First, referring to FIG. 7, the in-cell touch display device 100according to an exemplary embodiment includes the touch sensing unit 710and the common voltage supply 720. The touch sensing unit 710 measures achange in capacitance in one common electrode of the plurality of commonelectrodes CE, i.e., at least one touch electrode, to which a touchdriving signal TDS is applied, such that a touch and coordinates of atouched point are detected based on the change in capacitance. Thecommon voltage supply 720 supplies a common voltage Vcom to be appliedto all of the plurality of common electrodes CE.

As illustrated in FIG. 7, the touch sensing unit 710 may be separatelyprovided outside the data driver 120, or in some cases, may be providedinside the data driver 120.

In this regard, the data driver 120 may be implemented as at least onedata driver integrated circuit (DDIC) (also referred to as a “sourcedriver integrated circuit (SDIC)”). The touch sensing unit 710 may beprovided as a separate touch integrate circuit (IC) outside the DDIC.Alternatively, at least one touch sensing unit 710 may be providedinside the DDIC, thereby forming a one-chip structure.

FIG. 7 illustrates the signal applying structure in the unit touch areain which one common electrode CE11 is formed. The common electrode CE11is positioned on the first column and the first row of the plurality ofcommon electrodes CE11, CE12, CE13, CE14, CE21, CE22, CE23, CE24, CE31,CE32, CE33 and CE34.

Referring to FIG. 7, an i number of data lines DL1 to DLi (i=1, 2, . . .) and a j number of gate lines GL1 to GLj (j=1, 2, . . . ) are formed inthe unit common electrode area in which one common electrode CE11 isformed.

In addition, referring to FIG. 7, for example, an i*j number of pixels Pare defined at points in which the i number of data lines DL1 to DLi(i=1, 2, . . . ) and the j number of gate lines GL1 to GLj (j=1, 2, . .. ) intersect each other in the unit common electrode area in which onecommon electrode CE11 is formed.

Referring to FIG. 7, one data line and one gate line are connected toeach of the i*j number of pixels P formed in the unit common electrodearea in which one common electrode CE11 is formed. In addition, an innersignal line ISL through which the common voltage Vcom is transferred isconnected to each of the i*j number of pixels P.

Here, the inner signal line ISL is a signal line separate from thesignal line SL11 through which one common electrode CE11 is connected tothe data driver 120, and through which the common voltage Vcom or thetouch driving signal TDS is transferred. The inner signal line ISL isformed inside the unit common electrode area, connected to the signalline SL11.

First, a description will be given of the application (supply) of avariety of signals (a data voltage, a scanning signal and a commonvoltage) when the driving mode is display mode.

Referring to FIG. 7, when the driving mode is the display mode, the datadriver 120 supplies a corresponding data voltage Vdata (also referred toas a “pixel voltage”) to the i number of data lines DL1 to DLi throughan i number of data line multiplexers MUXd1 to MUXdi.

Referring to FIG. 7, when the driving mode is the display mode, the gatedriver 130 sequentially operates the j number of gate lines GL1 to GLjby supplying a turn-on voltage level scanning signal (e.g., VGH) to onegate line of the j number of gate lines GL1 to GLj and a turn-offvoltage level scanning signal (e.g., VGL) to the other gate lines of thej number of gate lines GL1 to GLj.

Referring to FIG. 7, when the driving mode is the display mode, thecommon voltage supply 720 outputs the common voltage Vcom to the signalline SL11 and the inner signal line ISL through, for example, a commonelectrode multiplexer MUXs of the data driver 120, thereby applying thecommon voltage Vcom to the common electrode CE11 corresponding to theunit common electrode area. The common voltage Vcom is applied to all ofthe common electrodes CE11, CE12, CE13, CE14, CE21, CE22, CE23, CE24,CE31, CE32, CE33 and CE34.

Subsequently, a description will be given of the application (supply) ofa signal when the driving mode is a touch mode.

Referring to FIG. 7, when the driving mode is the touch mode, forexample, the touch sensing unit 710 supplies the touch driving signalTDS to the common electrode CE11 corresponding to the unit commonelectrode area, as required, through the common multiplexer MUXs of thedata driver 120.

In addition, referring to FIG. 7, when the driving mode is the touchmode, for example, the sensing unit 710 and the gate driver 130 apply aload-free driving signal LFDS_gate, the phase and voltage width of whichcorrespond to those of the touch driving signal TDS, to the j number ofgate lines GL1 to GLj as required.

Referring to FIG. 7, when the driving mode is the touch mode, forexample, the touch sensing unit 710 applies a load-free driving signalLFDS_data to the i number of data lines DL1 to DLi through the i numberof data line multiplexers MUXd1 to MUXdi of the data driver 120 asrequired. The phase and voltage width of the load-free driving signalLFDS_data correspond to those of the touch driving signal TDS.

In addition, the i number of data line multiplexers MUXd1 to MUXdiillustrated in FIG. 7 may be implemented as a single data linemultiplexer.

The structure and method enabling the gate driver 130 to output thescanning signal or the load-free driving signal LFDS_gate to the gateline in FIG. 7 will be described in greater detail with reference toFIG. 8.

FIG. 8 conceptually illustrates a circuit in which the gate driver 130outputs a scanning signal or a load-free driving signal LFDS_gatedepending on the driving mode of the in-cell touch display device 100according to an exemplary embodiment.

Referring to FIG. 8, the gate driver 130 of the in-cell touch displaydevice 100 according to an exemplary embodiment outputs a scanningsignal to a corresponding gate line GL in a display mode, and outputs aload-free driving signal LFDS_gate corresponding to a touch drivingsignal TDS to a corresponding gate line GL in a touch mode.

Referring to FIG. 8, the in-cell touch display device 100 according toan exemplary embodiment further includes a circuit 800 enabling the gatedriver 130 to selectively output one of the scanning signal VGG/VGL andthe load-free driving signal LFDS_gate to the gate line.

Referring to FIG. 8, the circuit 800 includes a level shifter (L/S) 810and a multiplexer 820. The level shifter 810 generates the load-freedriving signal LFDS_gate corresponding to the touch driving signal basedon an input timing signal. The multiplexer 820 selectively outputs oneof the input scanning voltage VGG/VGL and the input load-free drivingsignal LFDS_gate to the gate driver 130.

The timing signal is a type of clock signal required for the levelshifter 810 to generate the load-free driving signal LFDS_gatecorresponding to the touch driving signal.

Referring to FIG. 8, for example, the level shifter 810 can modulate ascanning voltage (e.g., a low level scanning voltage VGL) insynchronization with the touch driving signal based on the input timingsignal, thereby generating the load-free driving signal LFDS_gatecorresponding to the touch driving signal.

In addition, referring to FIG. 8, the in-cell touch display device 100according to an exemplary embodiment further includes a micro controlunit (MCU) 830 that outputs the timing signal required for thegeneration of the load-free driving signal LFDS_gate to the levelshifter 810.

The micro control unit 830 can have a touch enable signal input theretofrom the timing controller 140, and can output the input touch-enablesignal to the multiplexer 820.

The multiplexer 820 can selectively output one of the scanning voltageVGG/VGL and the load-free driving signal LFDS_gate to the gate driver130 based on the touch enable signal input from the timing controller140 or the micro control unit 830. Accordingly, the gate driver 130generates a scanning voltage according to whether a scanning signal is ahigh-level voltage VGH or a low-level voltage VGL and subsequentlyoutputs the generated scanning voltage to the gate line, or outputs theload-free driving signal LFDS_gate to the gate line.

The touch enable signal may vary depending on the driving mode.

For example, when the driving mode is display mode, the touch enablesignal may be a low-level signal. When the driving mode is touch mode,the touch enable signal may be a high-level signal

The touch enable signal enables the level shifter 810 and themultiplexer 820 to recognize whether the current point of time of theoperation is in the display mode period or the touch mode period.

The micro control unit 830 may be provided outside or inside the datadriver 120.

Specifically, the micro control unit 830 may be provided separate fromthe DDIC of the data driver 120 or may be implemented as an internalunit of the DDIC of the data driver 120.

Referring to FIG. 8, the in-cell touch display device 100 according toan exemplary embodiment further includes a power management integratedcircuit 840 that outputs the scanning voltage VGH/VGL to the multiplexer820.

The power management integrated circuit 840 may be provided outside orinside the data driver 120.

Specifically, the power management integrated circuit 840 may beprovided as a unit separate from the DDIC of the data driver 120 or maybe implemented as an internal unit included inside the DDIC of the datadriver 120.

As illustrated in FIG. 8, the circuit 800 may be provided as a separateunit outside the gate driver 130. In this case, it is possible torealize the function of the gate driver 130 that selectively outputs oneof the scanning signal VGH/VGL and the load-free driving signalLFDS_gate to the gate line without changing the design of any of thegate driver 130, the timing controller 140, the micro control unit 830and the power management integrated circuit 840.

The circuit 800 may be, of course, provided as an internal unit of thegate driver 130.

In addition, the circuit 800 may be disposed on a source printed circuitboard (PCB) on which the data driver 120 may be disposed, may bedisposed on a control PCB on which the timing controller 140 may bedisposed, or in some cases, may be provided as a chip disposed on thepanel 110.

In the in-cell touch display device 100 according to an exemplaryembodiment, the timing controller 140 may be provided as a part separatefrom either the data driver 120 or the gate driver 130. Alternatively,in some cases, the timing controller 140 may be provided inside the datadriver 120, i.e., the DDIC of the data driver 120.

According to one or more embodiments of the present invention as setforth above, the in-cell touch display device 100 can prevent parasiticcapacitance that would otherwise increase the load of the touchoperation, lower the accuracy of the touch sensing, or make the touchsensing impossible.

According to one or more embodiments of the present invention, thein-cell touch display device 100 provides an efficient gate line drivingsystem that can prevent parasitic capacitance.

According to one or more embodiments of the present invention, thein-cell touch display device 100 can prevent parasitic capacitancewithout a change in the design of existing parts, such as the gatedriver 130 and the power management integrated circuit 840.

The foregoing descriptions and the accompanying drawings have beenpresented in order to explain the certain principles of one or moreembodiments of the present invention. A person skilled in the art towhich the invention relates can make many modifications and variationsby combining, dividing, substituting for or changing elements withoutdeparting from the principle of one or more embodiments of theinvention. The foregoing embodiments disclosed herein shall beinterpreted as illustrative only not as limitative of the principle andscope of the invention. It should be understood that the scope of theinvention shall be defined by the appended Claims and all of theirequivalents fall within the scope of the invention.

What is claimed is:
 1. An in-cell touch display device comprising: apanel including a plurality of data lines, a plurality of gate lines anda plurality of touch electrodes disposed thereon, wherein a touchdriving signal is applied to the plurality of touch electrodes when adriving mode is a touch mode; a data driver configured to drive theplurality of data lines; a gate driver configured to drive the pluralityof gate lines, wherein the gate driver sequentially outputs a scanningsignal for driving the plurality of gate lines to the plurality of gatelines when the driving mode is a display mode, and outputs a load-freedriving signal corresponding to the touch driving signal to at least onegate line of the plurality of gate lines when the driving mode is thetouch mode; a level shifter configured to generate the load-free drivingsignal; and a multiplexer configured to input a scanning voltage or theload-free driving signal to the gate driver depending on the drivingmode.
 2. The in-cell touch display device according to claim 1, whereinthe plurality of touch electrodes are in shape of blocks separated fromeach other.
 3. The in-cell touch display device according to claim 1,wherein the plurality of touch electrodes include a plurality of touchmode electrodes to which the touch driving signal is applied only in thetouch mode, or a plurality of common mode electrodes to which a displaydriving signal is applied in the display mode and the touch drivingsignal is applied in the touch mode.
 4. The in-cell touch display deviceaccording to claim 3, wherein, when the plurality of touch electrodesare the common mode electrodes, a plurality of common electrodes formedas blocks on the panel for displaying an image function as the pluralityof touch electrodes, wherein a common voltage is applied as the displaydriving signal to the plurality of touch electrodes corresponding to theplurality of common electrodes formed as the blocks on the panel whenthe driving mode is the display mode, and the touch driving signal isapplied to at least one touch electrode of the plurality of touchelectrodes when the driving mode is the touch mode.
 5. The in-cell touchdisplay device according to claim 4, wherein signal lines are disposedon the panel, each of the signal lines being connected to acorresponding touch electrode of the plurality of touch electrodes,wherein the plurality of signal lines transfer the common voltage to thetouch electrodes connected thereto in the display mode, and transfer thetouch driving signal to the touch electrodes connected thereto in thetouch mode.
 6. The in-cell touch display device according to claim 1,wherein, in the touch mode, the gate driver outputs the load-freedriving signal corresponding to the touch driving signal to all of theplurality of gate lines, or outputs the load-free driving signalcorresponding to the touch driving signal to at least one gate line ofthe plurality of gate lines formed at a position in which the at leastone gate line is to form parasitic capacitance with at least one touchelectrode of the plurality of touch electrodes to which the touchdriving signal.
 7. The in-cell touch display device according to claim1, wherein, in the touch mode, the data driver outputs the load-freedriving signal corresponding to the touch driving signal to all of theplurality of data lines, or outputs the load-free driving signalcorresponding to the touch driving signal to at least one data line ofthe plurality of data lines formed at a position in which the at leastone data line is to form parasitic capacitance with at least one touchelectrode of the plurality of touch electrodes to which the touchdriving signal is applied.
 8. The in-cell touch display device accordingto claim 1, wherein the level shifter generates the load-free drivingsignal corresponding to the touch driving signal by modulating thescanning voltage in synchronization with the touch driving signal basedon an input timing signal.
 9. The in-cell touch display device accordingto claim 8, further comprising a micro control unit configured to outputthe timing signal used for generation of the load-free driving signal tothe level shifter.
 10. The in-cell touch display device according toclaim 9, wherein the micro control unit has a touch enable signal inputthereto from a timing controller controlling the data driver and thegate driver, and outputs the input touch-enable signal to themultiplexer.
 11. The in-cell touch display device according to claim 10,wherein the multiplexer selectively outputs one of the scanning voltageand the load-free driving signal to the gate driver based on the touchenable signal input from the timing controller or the micro controlunit.
 12. The in-cell touch display device according to claim 9, whereinthe micro control unit is provided inside or outside the data driver.13. The in-cell touch display device according to claim 1, furthercomprising a power management integrated circuit configured to outputthe scanning voltage to the multiplexer.
 14. The in-cell touch displaydevice according to claim 13, wherein the power management integratedcircuit is provided inside or outside the data driver.
 15. The in-celltouch display device according to claim 1, further comprising a timingcontroller configured to control the data driver and the gate driver,wherein the timing controller is provided inside or outside the datadriver.
 16. The in-cell touch display device according to claim 1,further comprising a touch sensing unit configured to measure a changein capacitance of at least one common electrode of the plurality ofcommon electrodes to which the touch driving signal is applied, a touchand coordinates of a touched point being detected based on the change incapacitance.
 17. The in-cell touch display device according to claim 16,wherein the touch sensing unit is provided inside or outside the datadriver.